WorldWide Drilling Resource

Showing You the Ropes Adapted from Information by WireCo WorldGroup Whether it’s for the rotary drilling line, sandline, or mast raising line, wire ropes provide the strength necessary for efficient well drilling. No single rope can do it all, which is why wire ropes are available in various combinations with specific per- formance traits depending on design, engineering, materials, and composition. When selecting your wire rope, there’s a lot to consider. A rope with fewer but larger outside wires per strand will deliver more abrasion resistance, while rope with a greater number of smaller outside wires per strand, allows the rope to bend more freely which will increase fatigue life; but at the same time the smaller wires are more susceptible to abrasion. You should choose the rope you need based on the type of operation to be performed. Different tasks demand different characteristics, and having the right rope for each task can be critical to the overall success of your operation. Here are some of the things to consider: ) Fatigue Resistance - This involves metal fatigue of the wires making up the rope. For high fatigue resistance, the wires must be capable of bending repeatedly under stress. To increase fatigue resistance, use a rope with a large number of wires. Rope made of several wires will have greater fatigue resistance than a rope made of fewer, larger wires because smaller wires have greater ability to bend as the rope passes over sheaves or around drums. ) Abrasion Resistance - Refers to a rope’s ability to withstand metal being worn away along its exterior, causing defor- mation of the metal. The most common form of metal deformation is called peeni ng since outside wires appear to have been hammered. Typically, this happens on drums and sheaves, and is caused by rope-to-rope con- tact during spooling. The change in shape also impairs the wire’s movement whe n the rope bends. Peening causes metal fatigue, which may cause wire failure. ) Strength - Wire rope strength is usually measured in tons and is shown as m inimum breaking force (MBF). To determine the MBF, a new rope is put on a testing device and pla ced under tension until it breaks. A new rope will break at a figure equal to, or higher than, the MBF s hown for that par- ticular rope. Wire rope should never be used at, or near its MBF. Remember, don’t ever overload a wire rope. ) Crushing Resistance - Crushing happens when external pressure is placed on a rope, damaging it by distort- ing the cross-section shape of the rope, its strands, or core - or all three. Crushing resistance is a rope’s ability to withstand or resist external forces. When a rope is damaged by crushing, the wires, strands, and core are prevented from moving and adjusting normally. ) Bendability - Bendability relates to the ability of a rope to bend easily in an arc. There are four primary factors: the diameter of the wires making up the rope; rope and strand construction; metal composition of the wires / finish such as galvanizing; and the rope’s core (fiber core or IWRC). Small ropes have a tendancy to be more bendable than big ones. Additionally, fiber core ropes bend more easily than comparable IWRC ropes. All wire rope should be inspected regularly for wear and damage before each use. Remember, no matter how strong and durable your wire rope is, eventually, all wire ropes wear out and must be removed and replaced. This is why inspect- ing your rope is crucial. Fatigue resistance increases with more, smaller outside wires per strand. Abrasion resistance increases with fewer, larger outside wires per strand. G&O This company provides outstanding service! (503) 682-1001 rockmore-intl.com Rockmore International 48 JUNE 2018 WorldWide Drilling Resource ®